The application of coatings to glass containers to obtain increased mechanical strength, shatter resistance, scratch resistance during shipping and handling, increased number of recirculation cycles, resistance to fingerprints, and the like has been practiced for a long time. See, e.g., U.S. Pat. No. 3,944,100, EP 1,178,021, WO 2005/049219 and EP 1,555,249. In some cases, the coating has been applied to inhibit metal release from the glass or the container contents. For example, U.S. Pat. No. 5,592,044 uses a coating comprising a hydrolytic condensation product of a cross-linkable organofunctional hydrosilicon, a metal compound and an organic prepolymer cross-linkable with the hydrosilicon, to reduce lead leaching from lead crystal glass. US 2004/0199138 uses a silicone coating to prevent glass container leaching of aluminum from aluminum-containing pharmaceutical solutions therein.
The inks or paints in labels printed or affixed onto consumer goods containers frequently contain heavy metals, especially lead. The presence of these heavy metals can lead to hazardous exposure levels to consumers. Applied ceramic labels (ACLs) is an example of one such place where the presence of heavy metals can be found. ACLs are commonly used on various containers, and particularly on glass beverage bottles. Applied ceramic labeling is a process where ceramic inks are printed directly onto a bottle, often by screen printing. The bottles are subsequently heated sufficiently to fuse the ink directly to the bottle, creating a permanent decoration.